Neuromuscular Blocking Agents Flashcards
which classes of drugs provide muscle relaxation?
local anaesthetics
benzodiazepines
a2-adrenoreceptor agonists
guaiphenesin
neuromuscular blocking agents
why does ketamine require an adjunct muscle relaxant?
ketamine alone causes muscle rigidity
what is guaiphenesin?
a centrally acting muscle relaxant
where does guaiphenesin act?
internuncial neurones of spinal cord, brainstem and subcortical areas of brain
does guaiphenesin have analgesic/anaesthetic properties?
no
what effect does guaiphenesin have on the blood?
induces haemolysis if given at concentrations over 10%
which concentration of guaiphenesin induces haemolysis?
> 10%
what happens if guaiphenesin is given at concentrations over 10%?
causes haemolysis
how should guaiphenesin be administered?
slow IV only
why should guaiphenesin only be given IV?
causes tissue damage if goes perivascular
when is guaiphenesin typically given?
infused during induction of anaesthesia to reduce rigidity effects of ketamine
can be used in triple anaesthetic protocol in horses
what are the clinical indications for use of NMBAs?
relaxation of skeletal muscles for surgical access
facilitate control of ventilation
facilitate tracheal intubation in cats and pigs
ophthalmic surgery
assist reduction of dislocated joints and fractures
reduction in amount of anaesthetic required
how can NMBAs help with thoracic/abdominal surgery?
can help facilitate retraction in deep abdominal/thoracic surgery
how do NMBAs facilitate control of ventilation?
paralysis of respiratory muscles in order control ventilation more easily
ventilation during thoracotomy
when can NMBAs be useful in reduction of dislocated joints/fractures?
only if injury is recent - less success with longstanding injury
how may use of NMBAs help reduce amount of anaesthetic required?
aids muscles relaxation so that inhalant/injectable can be reduced
what separates the motor neurone and muscle cell?
synaptic cleft
what is separated by the synaptic cleft?
motor neurone and muscle cell
what is released from the nerve endings when a signal is recieved?
acetylcholine
when/where is acetylcholine released?
from the nerve endings when a signal is received
where does acetylcholine bind?
to the post-synaptic nicotinic receptor
how many acetylcholine subunits must be bound to the post-synaptic nicotinic receptor?
two
what does binding of the acetylcholine to the receptors result in?
muscle contraction
how is muscle contraction achieved?
binding of 2 Ach subunits to the post-synaptic nicotinic receptor